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United States Patent |
6,231,815
|
Bainczyk
,   et al.
|
May 15, 2001
|
Storage and transport system for sample material
Abstract
The invention concerns a system for the storage and transport of sample
material on absorbent material which is characterized in that the system
contains no test reagents and it additionally includes a closable
container containing a medium that can absorb moisture such as a desiccant
in addition to the absorbent material for absorbing a liquid sample.
Furthermore the system according to the invention can contain an agent to
stabilize the sample material and optionally further auxiliary substances.
Inventors:
|
Bainczyk; Gregor (Mannheim, DE);
Nagel; Rolf (Burstadt, DE);
Leininger; Helmut (Mannheim, DE);
Lerch; Rolf (Ilvesheim, DE)
|
Assignee:
|
Roche Diagnostics GmbH (Mannheim, DE)
|
Appl. No.:
|
974481 |
Filed:
|
November 20, 1997 |
Foreign Application Priority Data
| Dec 03, 1996[DE] | 196 49 938 |
| Oct 09, 1997[DE] | 197 44 550 |
Current U.S. Class: |
422/102; 73/864.72; 206/204; 427/61; 435/307.1 |
Intern'l Class: |
G01N 001/10; G01N 001/18 |
Field of Search: |
435/307.1,304.1
206/204
422/58,61,99,100,102,104
73/864.71,864.72
|
References Cited
U.S. Patent Documents
2317882 | Apr., 1943 | Boesel | 215/37.
|
3487275 | Dec., 1969 | Perrin et al. | 317/234.
|
4394144 | Jul., 1983 | Aoki | 55/281.
|
4559949 | Dec., 1985 | Levine | 436/66.
|
4667817 | May., 1987 | Im et al. | 206/204.
|
4816224 | Mar., 1989 | Vogel et al.
| |
4834234 | May., 1989 | Sacherer et al. | 206/204.
|
5183742 | Feb., 1993 | Omoto et al.
| |
5186843 | Feb., 1993 | Baumgardner et al.
| |
5262067 | Nov., 1993 | Wilk et al.
| |
5478752 | Dec., 1995 | Lerch et al.
| |
5520041 | May., 1996 | Haswell | 73/29.
|
5783759 | Jul., 1998 | Wielinger et al.
| |
Foreign Patent Documents |
63243756 | Mar., 1987 | JP.
| |
Other References
Clinical Chemistry vol. 29, pp.1080-1082 (1983).
Clinical Chemistry, vol. 28, pp. 386-387 (1982).
Clinical Chemistry, vol. 32, pp. 869-871 (1986).
DIN 53106 (May 1981) and English translation.
|
Primary Examiner: Alexander; Lyle A.
Attorney, Agent or Firm: Fulbright & Jaworski, LLP
Claims
What is claimed is:
1. A system for storage and transport of sample material on absorbent
material comprising a closable container containing a medium that absorbs
moisture and a first layer and a second layer of absorbent material for
absorbing a liquid sample attached to an inert support, said first layer
and said second layer of absorbent material arranged next to and touching
another on said inert support and contacted to enable transfer of liquid
such that liquid can pass from said first layer into said second layer
when said first layer is filled with liquid and said first layer can be
completely separated from said second layer after a sample material has
been applied and dried, said absorbent material for said first and said
second layers being selected from the group consisting of papers, filter
papers, fleeces, fabrics, knitted fabrics and membranes, and does not
contain test reagents.
2. The system of claim 1, wherein said absorbent material further comprises
auxiliary substances to spread the liquid sample.
3. The system of claim 1, wherein said absorbent material further comprises
a marking on the sample application zone.
4. The system of claim 1, wherein said system is provided with handling
instructions.
5. The system of claim 1, wherein said medium that absorbs moisture
comprises a dessicant.
6. The system of claim 5, wherein said desiccant is selected from the group
consisting of silica gels, zeolites, clays and combinations thereof.
7. The system of claim 1, wherein said closable container comprises a tube
that can be closed with a member selected from the group consisting of a
stopper and a cap.
8. The system of claim 7, wherein said stopper or cap comprises a
non-deformable, unbreakable material that is inert towards the sample.
9. The system of claim 8, wherein said tube is made of a member selected
from the group consisting of a plastic, a metal, alloys, paper, cardboard,
ceramics, and glass.
10. The system of claim 9, wherein said tube is made of a material selected
from the group consisting of polyethylene, polypropylene and aluminum.
11. The system of claim 1, wherein said medium which absorbs moisture is
permanently attached to said closable container or to a part thereof.
12. The system of claim 1, wherein said closable container comprises a
member selected from the group consisting of an envelope having a foldable
edge and a bag having a foldable edge.
13. The system of claim 1, wherein said absorbent material further
comprises stabilizers for the sample.
14. The system of claim 13, wherein said absorbent material comprises a
boric acid buffer with a pH larger than or equal to 10.5.
15. The system of claim 7, wherein said tube comprises a non-deformable
unbreakable material that is inert towards the sample.
16. The system of claim 9, wherein said paper is coated with a member
selected from the group consisting of plastic, metal, and alloys.
17. The system of claim 9, wherein said cardboard is coated with a member
selected from the group consisting of plastic, metal, and alloys.
18. The system of claim 13, wherein said absorbent material further
comprises a transition metal salt.
Description
FIELD OF THE INVENTION
The invention concerns a system for storing and transporting sample
material on absorbent material.
BACKGROUND OF THE INVENTION
The glycation of haemoglobin and serum proteins is increased in patients
with diabetes mellitus. The increase is dependent on the glucose
concentration and the incubation period of the protein with glucose. In
these cases the serum proteins, including haemoglobin, are not glycated
enzymatically but rather by means of an uncatalysed chemical reaction of
glucose with amino groups of proteins. Experts assume that the
concentration of a particular protein-glucose adduct reflects the glucose
concentration over a particular period as well as the turn-over rate of
the protein. Glycated haemoglobin is regarded as an indicator of the
average blood glucose concentration during the last two to three months
before the blood collection and examination. Glycated serum protein shows
the blood glucose concentration during a shorter period of time. The
determination of glycated protein such as glycated haemoglobin
(HbA.sub.1c) or glycated serum protein is therefore considerably important
for the long-term glycemic control of diabetes patients.
In order to examine blood for the content of glycated protein the sample
must often be transported to a far distant laboratory. The content of
glycated protein in the sample should not change during this transport
period and during a possible subsequent waiting period. The examination of
blood samples which had been stored for a long period for glycated
haemoglobin is reported in Clinical Chemistry 29, 1080-1082 (1983). This
shows that whole blood can be stored up to 21 days at room temperature
with essentially no change in the HbA.sub.1c content.
However, the transport of liquid blood samples is complicated and involves
risks such as breakage of the transport vessel. In addition the puncture
of a vein is necessary to collect whole blood although the small amounts
obtained by withdrawing capillary blood from the finger pad would be
sufficient for the analysis. Thus methods have been developed for the
transport and analysis of smaller amounts of sample in which capillary
blood is applied to filter paper and allowed to dry there. The filter
paper is subsequently transported to the site of the examination. Here a
disk containing the sample is cut out from the filter paper, eluted and
the eluate is examined. The report in Clinical Chemistry 28, 386-387
(1982) refers to such a method. In this report it is stated that the
content of glycated protein changes considerably compared to the original
sample during blood sample storage on filter paper. After storage of whole
blood on filter paper considerably increased measured values for glycated
protein are found.
The impregnation of filter paper with glucose oxidase to prevent the
increase in the content of glycated haemoglobin caused by storage of blood
on filter paper is described in Clinical Chemistry 32, 869-871 (1986).
However, impregnation with glucose oxidase was not able to completely
prevent the increase of glycated protein. The false increase in the values
can only be reduced by this measure. A further disadvantage of
impregnating with glucose oxidase is its own instability during storage
under the usual storage conditions.
Similar conclusions are reached by an article in Diabetes Care 10, 352-355
(1987). Here it is reported that the treatment of filter paper with
glucose oxidase or with ethanol cannot satisfactorily prevent a false
increase in the values for glycated haemoglobin when blood is stored on
filter paper.
Apart from the poor stability of the sample, a further disadvantage of the
methods described in the state of the art for the transport and storage of
sample materials is that the liquid sample has to be completely dried
before the final packaging. For this the filter paper has to be typically
dried for 10 to 60 minutes in the air. Incompletely dried samples can lead
to non-reproducible test results or for example contaminate the shipping
packaging.
OBJECT AND SUMMARY OF THE INVENTION
The object of the present invention was therefore to eliminate the
disadvantages of the state of the art. In particular the content of
glycated protein should be stabilized in a sample when stored on an
absorbent material. After storage of the glycated protein on an absorbent
material a value should be found for the glycated protein which
corresponds to that found after sample collection and before storage.
Furthermore it should simplify the handling of the carrier containing the
sample material and make it safer.
This object is achieved by the subject matter characterized in more detail
in the patent claims.
The invention concerns a system for storing and transporting sample
material. The system is composed of an absorbent material for absorbing a
liquid sample, a closable container in which the material can be stored
and transported and a moisture absorbent medium.
An essential feature of the system according to the invention is that the
system itself contains no test reagents. In particular the absorbent
material which serves to absorb the sample material contains no test
reagents.
In this connection test reagents are those reagents or substances which are
usually contained in analytical test elements such as colorimetric test
strips or electrochemical sensors and biosensors and are used to detect a
target analyte. In other words test reagents are substances which interact
with the target analyte and allow it to be directly or indirectly detected
i.e. optionally not until after the addition of other reagents. Examples
are enzymes, coenzymes, dyes, mediators, pH and redox indicators,
immunological detection reagents such as antibodies or antigens,
ionophores, complexing agents etc..
Test reagents do not include reagents or substances that are not used
directly to detect a target analyte. Such substances must not interact
with the target analyte in the sample in a manner which would allow its
detection. Examples of these are stabilizers, which are also understood to
include enzyme substrates and coenzymes which mainly serve to stabilize
the analyte, buffer substances, spreading agents and other common
substances familiar to a person skilled in the art.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is a preferred embodiment of an element according to the present
invention;
FIG. 2 is a side view of a preferred embodiment of an element according to
the present invention; and
FIG. 3 is a preferred embodiment of the system of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The system according to the invention is suitable for transporting and
storing sample material to be analysed especially liquid samples and above
all body fluids such as blood, plasma, serum, urine, saliva etc. The
element according to the invention is particularly preferably used to
transport and store blood samples.
Papers, filter papers, fleeces, fabrics, knitted fabrics and membranes
which are optionally attached to an additional inert support as are known
to a person skilled in the art have proven to be suitable as absorbent
materials for the system according to the invention. Fibrous materials are
preferably used as absorbent materials although basically non-fibrous
materials such as for example membranes can also be used. Preferred
fibrous absorbent materials are fleeces, fabrics or knitted fabrics.
Fleeces are quite especially preferred. The fibrous materials can contain
glass, cellulose, polyester fibres and also viscose and polyvinyl alcohol.
Fleece materials containing meltable copolyester fibres in addition to
glass fibres, polyester fibres, polyamide fibres, cellulose fibres or
cellulose derivative fibres as described in the European Patent
Application 0 571 941 can also be used advantageously in the element
according to the invention.
Depending on the analyte to be analysed it must be ensured that it can
subsequently be reproducibly eluted again after application and drying of
the sample material on the absorbent material. For this purpose a person
skilled in the art can carry out simple elution experiments in order to be
certain.
The absorbency can be determined according to DIN 53106. For this purpose
the lower end of samples of 200+/-1 mm in length and 15+/-0.1 mm in width
are immersed perpendicularly 25 mm into distilled water and the distance
which the water migrates within 10 min is measured in mm. A person skilled
in the art knows how different absorbencies can be adjusted in materials
with the same components. For example when manufacturing fleeces different
thicknesses can be used. The thicker the fibres used the lower is the
absorbency. A further method is to vary the density of fleeces. The
absorbency is reduced by an increase in density.
When using fabrics, fabrics with finer fibres have a higher absorbency than
fabrics with coarser fibres. However, the absorbency can also be
controlled by different types of twisting of the threads. In addition
variations in the absorbency can be achieved via the type of weaving.
Further possibilities for varying the absorbency can be achieved by using
different mixtures of fibres. Thus for example the absorbency is reduced
by the addition of hydrophobic fibres.
Stiff materials come into particular consideration as the inert support
material for the absorbent materials that can be used according to the
invention such as for example plastic foils, cardboard, coated paper etc.
The absorbent material is attached to the inert support material in such a
way that the uptake of liquid by the absorbent materials is not impaired.
This can be achieved by using a double-sided adhesive tape or for example
also by using hot-melt adhesive.
In a particularly preferred embodiment of the invention the two layers of
absorbent material are located on the support material next to and
touching one another in such a way that liquid can pass from the first
layer into the second layer when the first layer is filled with liquid.
The absorbency of the matrix material of the first layer should be the
same as or greater than that of the second neighbouring layer. This avoids
the development of interfering suction effects when sample material is
applied to the first layer.
In the particularly preferred embodiment described above the layers of the
absorbent material must be attached to the inert support in such a way
that the first layer can be completely separated from the second layer
after applying and drying the liquid sample material. This is especially
possible when the first layer is only attached relatively loosely or at
certain points.
Furthermore in the particularly preferred embodiment described above the
two layers of absorbent material must be located on the support material
next to and touching one another in such a way that liquid can pass from
the first layer into the second layer when the first layer is filled with
liquid. This is then possible when at least the edges of the two layers
are touching. It is even better, however, if there is a slight overlap of
the two layers. It is particularly preferred that the layers are arranged
such that the second layer slightly overlaps the first layer.
For the particularly preferred embodiment described above the size of the
absorbent material layers must be selected such that the first layer,
which is later also to be used as the analytical layer, can be completely
filled with the sample liquid. Excess sample liquid is then taken up by
the second layer. The amounts of sample that are adequate to determine a
particular analyte depends on the type of analyte to be determined.
However, as a rule 5-20 .mu.l and usually 10 .mu.l sample is adequate.
This volume must be taken up by the first matrix layer and capable of
being eluted again later. For safety reasons the second matrix layer which
has the function of a suction layer should be able to absorb a larger
volume. Suction volumes of 10-50 .mu.l preferably 10-30 .mu.l particularly
preferably 20 .mu.l are usually adequate for this purpose. It is expedient
that the usual dimensions of the absorbent material layers are such that
the suction volume of the two layers taken together is at least 30 .mu.l
and preferably at least 50 .mu.l. Such a dimension ensures that the same
amount of sample is applied on the first matrix layer of various elements
according to the invention with small as well as with large drops of
liquid. In order to achieve an adequate suction volume the smaller first
layer usually has an area of 3.times.3 to 8.times.8 mm.
The particularly preferred arrangement of absorbent material layers
described above enables a homogeneous distribution of liquid sample
material to be achieved in the first layer. Due to the fact that the first
layer should be completely filled with liquid sample material,
concentration gradients of the analyte which are otherwise always observed
in the border zones of the elements of the state of the art cannot form
within this layer. Hence differences in measurement due to concentration
are avoided when determining analytes.
Various arrangements of the layers on the support material can be envisaged
in order to separate the first and second layer of the absorbent material
in the particularly preferred embodiment described above. Quite especially
preferred embodiments of absorbent materials attached to a support are
shown in FIGS. 1 and 2
The element of the invention according to FIG. 1 carries layers of an
absorbent material 1,2 at one end of an inert support material 3. The
layers are attached to the support material 3 by means of a double-sided
adhesive tape 4. Layers 1,2 are arranged on the support material 3 in such
a way that they are located at the end of the support material 3. The
first layer of the absorbent material 1 which is intended for the sample
application is closest to the end of the support material 3. It is
slightly overlapped by the second layer of the absorbent material 2 which
takes up the excess liquid of the sample material when the first layer 1
is filled. At the end of the support material 3 there is a recess 5 in the
support material 3 below the first layer 1. This recess 5 enables or
facilitates gripping of the first layer 1 for example with tweezers in
order to remove it from the element for the purpose of elution and
subsequent analytical steps.
In the element according to the invention shown in FIG. 2 the two layers of
the absorbent material 1,2 are attached to the inert support material 3 in
such a way that the two opposite ends of the support material 3 are free
and can be grasped with fingers. The two layers of the absorbent material
1,2 are attached to the support material 3 by means of double-sided
adhesive tape 4,6. The support material 3 has a predetermined breaking
point 7 which is arranged such that the element can be divided at this
point into two parts by bending, breaking or tearing such that one of the
parts carries the first layer of the absorbent material 1 and the other
carries the second layer of the absorbent material 2. In the case of a
plastic foil as the support material 3 the predetermined breaking point 7
can be a notch. However, an appropriate perforation may also be present at
this position which enables two separate parts to be obtained when the
element is bent at this position.
In a further preferred embodiment the absorbent material of the system
according to the invention contains auxiliary substances which are
suitable for spreading the liquid sample. Such auxiliary substances are
known among experts and a person skilled in the art is familiar with their
use. The spreading of the sample enables a uniform homogeneous spreading
of the sample material on and in the absorbent material. If for example
filter paper is used as the absorbent material, this measure ensures that
small samples of the filter paper containing the previously applied sample
material which have been cut out of or punched out of the filter paper for
elution purposes contain reproducible amounts of sample material.
In a further preferred embodiment the sample application zone of the
absorbent material is marked. In this case the mark can be directly
applied on or in or contained on or in the absorbent material or
optionally be applied to the inert support. This makes it easier for the
user to precisely apply the sample to the preferred application site. This
measure also serves to increase the reproducibility of the sample
application.
Furthermore it is preferred that handling instructions for the user or
users of the system according to the invention are contained within it.
The handling instructions are particularly preferably attached to the
absorbent material and optionally to the inert support or the closable
container. The handling instructions are quite especially preferably
attached to the absorbent material.
The closable container of the system according to the invention serves to
mechanically stabilize the absorbent material containing the sample
material during storage and transport. The closable container is
preferably composed of a stiffened envelope with a foldable edge, a bag
with a foldable edge which can optionally be inserted into a stiff
envelope or a tube that can be closed with a stopper or cap. A tube that
can be closed with a stopper or cap is particularly preferably used. The
tube is preferably composed of a non-deformable material that is resistant
to fracture and is inert towards the sample, for example plastics, metals,
alloys, paper or cardboard which are optionally coated with plastics,
metals and/or alloys, ceramics or glass. The use of polyethylene,
polypropylene or aluminium has proven to be particularly preferable.
In addition to the mechanical stabilization the closable container in
combination with a medium that absorbs moisture ensures that there is
always a lower air humidity in the inside of the container in the presence
of a medium that absorbs moisture than in the outer surrounding atmosphere
whereby moisture or humidity is preferably understood as water. For this
purpose it is preferable to use a desiccant as is familiar to a person
skilled in the art. Silica gels, zeolites or clays are quite especially
preferably used as desiccants optionally also combinations thereof.
In a particularly preferred embodiment the moisture absorbing medium is
permanently attached to the closable container or at least a part thereof.
It is quite especially preferable to integrate a desiccant in the cap or
stopper of a tube in such a way that a drying action occurs exclusively in
the interior of the tube. Such a particularly preferred embodiment of the
system according to the invention is shown in FIG. 3. FIG. 3 shows a
sample carrier 1 which is inserted into a tube 2 with a close-fitting
stopper 3 containing a desiccant 4.
In a further preferred embodiment the absorbent material of the system
according to the invention contains one or several stabilizers for the
sample material. It has for example turned out that sample material
containing glycated protein that is located on an absorbent material can
be stored very well without any essential change in the content of
glycated protein if the absorbent material is impregnated with boric acid
buffer with a pH of greater than or equal to 10.5 or if the absorbent
material carries a transition metal salt. In this case the concentration
of the boric acid buffer is of secondary importance. Particularly good
results are obtained if the boric acid buffer has a pH value of more than
or equal to 11. Suitable buffer concentrations are in the range between
300 and 1000 mmol/l, which corresponds to about 8.6-62 g/100 ml.
Transition metal salts such as nickel or copper salts have a similarly
good stabilizing action. Nickel salts are particularly preferred.
Water-soluble transition metal salts are preferably used. Corresponding
chlorides are for example well suited. In order to have an adequate
stabilizing effect transition metal salt concentrations on the absorbent
material of more than 5 g/m.sup.2 and particularly preferably of more than
10 g/m.sup.2 have proven to be suitable.
The system according to the invention is suitable for storing and
transporting sample material to be analysed. Analytes which can be
transported and stored in this manner include glucose and glycosylated
haemoglobin (HbA.sub.1c). However, essentially any analyte which can be
dissolved by appropriate eluants and then can be measured in this solution
can be measured in this manner. Basically these are for example all
analytes that can be determined by means of enzymatic, immunological and
other test procedures. Without wishing to limit the scope of the possible
analytes, those analytes are also mentioned at this point which can be
used to detect infectious diseases such as for example virus antibodies or
viral components for the determination of hepatitis and HIV. The samples
which contain these can be advantageously transported in this manner to
the site of analysis. The use of a moisture absorbing medium in the system
according to the invention ensures a safe handling by the end user since
the user does not have to pay attention to sample drying before packing
the absorbent material containing the sample. Furthermore a good stability
of the sample material is ensured.
The invention is elucidated further in the following example.
EXAMPLE 1
Stabilizing HbA.sub.1c on an Absorbent Material by a Moisture Absorbent
Medium
A first layer 1 of an absorbent material is fixed with the aid of a
double-sided adhesive tape 4 to a polyester foil 3 of dimensions
49.times.6 mm with a semicircular punched hole 5 of 5 mm at a short-sided
end as shown in FIG. 1 in such a way that 0.5 to 1 mm of its width is
glued onto the adhesive tape 4. The later detachability is positively
influenced by this relatively narrow attachment. The second layer 2 of the
absorbent material is glued in a width of 5 mm or more.
A fleece which has been manufactured on a paper machine which has the
following data is used for the first layer of absorbent material:
80 parts polyester fibres (fibre diameter 1.7 Dtex), 20 parts viscose, 20
parts polyvinyl alcohol; area weight 80 g/m.sup.2 ; suction height 102 mm
(DIN 53106).
This fleece was cut to a size of 6.times.6 mm. This matrix takes up ca. 10
.mu.l of liquid.
A fleece is used for the second layer of absorbent material which
corresponds to the first layer.
Ca. 10 .mu.l EDTA blood (samples 1 to 3) is applied in each case to the
elements manufactured in this manner and dried at room temperature for at
least 2 hours.
Sample 1 EDTA blood 9.5% HbA.sub.1c
Sample 2 EDTA blood 4.9% HbA.sub.1c
Sample 3 sample 2 supplemented with 400 mg/dl
.beta.-D(+)-glucose
In order to simulate a transport the sample carriers were stressed for 7
days at 20, 35 and 45.degree. C. at a humidity of 90%+/-8%. In this
experiment a portion of the sample carriers is stored in a conventional
envelope, a second portion is stored in a closable bag with a foldable
edge without a desiccant, a third portion is stored in a sealed bag with a
foldable edge containing a molecular sieve desiccant bag (Order No.
1602080, Boehringer Mannheim GmbH, Germany) and a fourth portion is stored
in a sealed tube containing a molecular sieve (Order No. 1775111,
Boehringer Mannheim GmbH, Germany).
After removing the first layer of the absorbent material, the material is
eluted for 1.5 to 2.5 h in 1 ml haemolysis reagent for the Tina-quant.RTM.
test of Boehringer Mannheim GmbH (Germany) (order number 1 488 457).
Subsequently HbA.sub.1c is determined according to the immunological
method of determination of Boehringer Mannheim GmbH (Germany) on a Hitachi
717 instrument from Boehringer Mannheim GmbH using reagent order number 1
488 414 from Boehringer Mannheim GmbH.
The measured results are summarized in table 1 for elements in which the
storage took place with and without moisture absorbing medium.
TABLE 1
Influence of 90% humidity on
HbA.sub.1c sample carriers on the recovery (%) of the initial value
Temperature [.degree. C.] Days storage 1 2 7
Storage in an envelope
20 Sample 1 93.2 95.2 77.1
35 Sample 1 76.1 62.2 <measuring range
45 Sample 1 51.3 25.2 not determined
20 Sample 2 99.1 101.5 90.5
35 Sample 2 92.6 86.4 <measuring range
45 Sample 2 72.8 49.2 not determined
20 Sample 3 103.0 104.7 97.2
35 Sample 3 96.9 90.7 <measuring range
45 Sample 3 49.1 54.9 not determined
Storage in a sealed bag with a foldable edge without desiccant
20 Sample 1 96.0 99.7 79.7
35 Sample 1 79.4 64.3 <measuring range
45 Sample 1 55.5 39.8 not determined
20 Sample 2 103.9 102.8 90.5
35 Sample 2 97.7 87.8 <measuring range
45 Sample 2 82.7 59.4 not determined
20 Sample 3 104.0 105.1 97.9
35 Sample 3 102.0 94.5 <measuring range
45 Sample 3 89.0 53.6 not determined
Storage in a sealed bag with a foldable edge containing desiccant
20 Sample 1 102.3 111.6 110.8
35 Sample 1 98.8 106.2 42.8
45 Sample 1 86.9 66.1 <measuring range
20 Sample 2 101.8 105.6 105.6
35 Sample 2 103.9 105.9 66.6
45 Sample 2 103.5 89.5 <measuring range
20 Sample 3 103.7 107.1 107.1
35 Sample 3 102.7 110.2 67.9
45 Sample 3 110.2 106.4 <measuring range
Storage in a sealed tube containing desiccant
20 Sample 1 107.2 109.7 110.7
35 Sample 1 101.8 110.0 111.8
45 Sample 1 106.0 112.9 118.6
20 Sample 2 103.9 107.3 101.8
35 Sample 2 102.1 105.6 109.3
45 Sample 2 105.2 109.3 112.7
20 Sample 3 101.7 106.8 102.7
35 Sample 3 104.4 107.1 109.2
45 Sample 3 106.1 111.5 112.9
It can be seen that the result is that storage in a closed container which
contains a moisture absorbing medium leads to such a stabilization of the
non-enzymatically glycosylated protein that adequately unchanged
concentration values are obtained even after temperature stress.
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